Evaluation of Phosphate Sorption Kinetics by Sugar Cane Bagasse Biochar

Application of agricultural residue biochars as an adsorbent is one of the most cost-effective and widely used methods to remove contaminants such as phosphate from water resources. In fact, the bagasse is the waste residues of sugar cane which is abundant in southern parts of Iran. The aim of this study was to investigate the kinetics of phosphate adsorption by bagasse biochar and determine the best kinetic model to interpret this phenomenon. After determining optimal pH, the effects of initial phosphate concentration and contact time on phosphate adsorption by sugarcane bagasse biochar were investigated and 7 kinetic models were used to study the patterns of P adsorption. Maximum adsorption obtained at the time of two hours. Kinetic models of the exponential function, parabolic diffusion, Elovich and first order reaction were compatible with the results but the exponential function model was the best. The half-life of phosphate adsorption in different concentrations varied from 30 minutes to 100 minutes and decreased with increasing initial P concentration. P adsorption rate constants increased as initial concentration of phosphate increased. High values of P adsorption parameters demonstrated that the sugar cane bagasse biochar could be used as an appropriate adsorbent for phosphate removal from aqueous solutions.